In this contribution the use of an artificial in situ-cofactor regeneration with [Fe(III)TSPPICI for enzymatic amino acid oxidation, exemplified for the L-glutamate dehydrogenase-catalyzed synthesis of a-ketoglutarate from sodium L-glutamate, is reported. In comparison of two L-glutamate dehydrogenases, the one isolated from Clostridium difficile turned out to be the preferred enzyme. At a substrate concentration of 15 mM of L-glutamate in situ-cofactor regeneration using [Fe(III)TSPP]CI as an "artificial NADH-oxidase" proceeded smoothly, leading to up to >99% overall conversion and 88% conversion related to the formation of alpha-ketoglutarate after 24h. At an increased concentration of 50 mM of L-glutamate, a somewhat decreased conversion of 43% was observed (which, however, corresponds to a nearly doubled volumetric productivity of 3.95 g/(Ld) compared to the experiments at 15 mM). Thus, the iron complex [Fe(III)TSPP]CI turned out to be capable to be used for cofactor regeneration of the cofactor NAD(+) for enzymatic amino acid oxidation. (C) 2014 Elsevier B.V. All rights reserved.